1. Field of the Invention
The invention relates to a multi-band antenna, and particularly to a multi-band antenna with simple structure adapted to be configured in a portable electrical device.
2. The Related Art
A portable communication device has an antenna structure that supports wireless communication in multiple operating frequency bands, such as global system mobile (GSM) and wideband code division multiple access (W-CDMA) nowadays. Many different types of antennas for the portable communication device are used, including helix, inverted-F, folded dipole, and retractable antenna structures. Helix antenna and retractable antenna are typically installed outside the portable communication device. Inverted-F antenna and folded dipole antenna are typically embedded inside the portable communication device case or housing.
Generally, embedded antennas are preferred over external antennas for the portable communication device owing to mechanical and ergonomic reasons. Embedded antennas are protected by the portable communication device case or housing and therefore tend to be more durable than external antennas. Nowadays, the portable communication is combined with wireless communication technology and data processing technology for multiple function purpose, such as a notebook. Therefore, the embedded antenna capable of operating at various wireless communication bands and being configured in the notebook is a development point.